diff options
Diffstat (limited to 'src/port/thread.c')
| -rw-r--r-- | src/port/thread.c | 152 |
1 files changed, 16 insertions, 136 deletions
diff --git a/src/port/thread.c b/src/port/thread.c index e164d017d4f..d6e1b269733 100644 --- a/src/port/thread.c +++ b/src/port/thread.c @@ -7,7 +7,7 @@ * * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group * - * $PostgreSQL: pgsql/src/port/thread.c,v 1.14 2003/11/29 22:41:31 pgsql Exp $ + * $PostgreSQL: pgsql/src/port/thread.c,v 1.15 2004/02/11 21:44:06 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -31,7 +31,7 @@ * strerror(). Other operating systems use pthread_setspecific() * and pthread_getspecific() internally to allow standard library * functions to return static data to threaded applications. And some - * operating systems have neither, meaning we have to do our own locking. + * operating systems have neither. * * Additional confusion exists because many operating systems that * use pthread_setspecific/pthread_getspecific() also have *_r versions @@ -50,18 +50,13 @@ * * The current setup is to try threading in this order: * - * use non-*_r function names if they are all thread-safe - * (NEED_REENTRANT_FUNCS=no) - * use *_r functions if they exist (configure test) - * do our own locking and copying of non-threadsafe functions - * - * The disadvantage of the last option is not the thread overhead but - * the fact that all function calls are serialized, and with gethostbyname() - * requiring a DNS lookup, that could be slow. + * use *_r function names if they exit + * (*_THREADSAFE=ye) + * use non-*_r functions if they are thread-safe * * One thread-safe solution for gethostbyname() might be to use getaddrinfo(). * - * See src/tools/thread to see if your operating system has thread-safe + * Run src/tools/thread to see if your operating system has thread-safe * non-*_r functions. */ @@ -73,7 +68,7 @@ char * pqStrerror(int errnum, char *strerrbuf, size_t buflen) { -#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(NEED_REENTRANT_FUNCS) && defined(HAVE_STRERROR_R) +#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(HAVE_STRERROR_R) /* reentrant strerror_r is available */ /* some early standards had strerror_r returning char * */ strerror_r(errnum, strerrbuf, buflen); @@ -81,18 +76,13 @@ pqStrerror(int errnum, char *strerrbuf, size_t buflen) #else -#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_STRERROR_R) - static pthread_mutex_t strerror_lock = PTHREAD_MUTEX_INITIALIZER; - pthread_mutex_lock(&strerror_lock); +#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && !defined(STRERROR_THREADSAFE) +#error This platform can not create a thread-safe version because strerror is not thread-safe and there is no reentrant version #endif /* no strerror_r() available, just use strerror */ StrNCpy(strerrbuf, strerror(errnum), buflen); -#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_STRERROR_R) - pthread_mutex_unlock(&strerror_lock); -#endif - return strerrbuf; #endif } @@ -106,7 +96,7 @@ int pqGetpwuid(uid_t uid, struct passwd *resultbuf, char *buffer, size_t buflen, struct passwd **result) { -#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(NEED_REENTRANT_FUNCS) && defined(HAVE_GETPWUID_R) +#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(HAVE_GETPWUID_R) /* * Early POSIX draft of getpwuid_r() returns 'struct passwd *'. * getpwuid_r(uid, resultbuf, buffer, buflen) @@ -117,53 +107,14 @@ pqGetpwuid(uid_t uid, struct passwd *resultbuf, char *buffer, #else -#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_GETPWUID_R) - static pthread_mutex_t getpwuid_lock = PTHREAD_MUTEX_INITIALIZER; - pthread_mutex_lock(&getpwuid_lock); +#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && !defined(GETPWUID_THREADSAFE) +#error This platform can not create a thread-safe version because getpwuid is not thread-safe and there is no reentrant version #endif /* no getpwuid_r() available, just use getpwuid() */ *result = getpwuid(uid); - -#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_GETPWUID_R) - - /* Use 'buffer' memory for storage of strings used by struct passwd */ - if (*result && - strlen((*result)->pw_name) + 1 + - strlen((*result)->pw_passwd) + 1 + - strlen((*result)->pw_gecos) + 1 + - /* skip class if it exists */ - strlen((*result)->pw_dir) + 1 + - strlen((*result)->pw_shell) + 1 <= buflen) - { - memcpy(resultbuf, *result, sizeof(struct passwd)); - strcpy(buffer, (*result)->pw_name); - resultbuf->pw_name = buffer; - buffer += strlen(resultbuf->pw_name) + 1; - strcpy(buffer, (*result)->pw_passwd); - resultbuf->pw_passwd = buffer; - buffer += strlen(resultbuf->pw_passwd) + 1; - strcpy(buffer, (*result)->pw_gecos); - resultbuf->pw_gecos = buffer; - buffer += strlen(resultbuf->pw_gecos) + 1; - strcpy(buffer, (*result)->pw_dir); - resultbuf->pw_dir = buffer; - buffer += strlen(resultbuf->pw_dir) + 1; - strcpy(buffer, (*result)->pw_shell); - resultbuf->pw_shell = buffer; - buffer += strlen(resultbuf->pw_shell) + 1; - - *result = resultbuf; - } - else - { - *result = NULL; - errno = ERANGE; - } - - pthread_mutex_unlock(&getpwuid_lock); -#endif #endif + return (*result == NULL) ? -1 : 0; } #endif @@ -181,7 +132,7 @@ pqGethostbyname(const char *name, struct hostent **result, int *herrno) { -#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(NEED_REENTRANT_FUNCS) && defined(HAVE_GETHOSTBYNAME_R) +#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(HAVE_GETHOSTBYNAME_R) /* * broken (well early POSIX draft) gethostbyname_r() which returns * 'struct hostent *' @@ -191,87 +142,16 @@ pqGethostbyname(const char *name, #else -#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_GETHOSTBYNAME_R) - static pthread_mutex_t gethostbyname_lock = PTHREAD_MUTEX_INITIALIZER; - pthread_mutex_lock(&gethostbyname_lock); +#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && !defined(GETHOSTBYNAME_THREADSAFE) +#error This platform can not create a thread-safe version because getaddrinfo is not thread-safe and there is no reentrant version #endif /* no gethostbyname_r(), just use gethostbyname() */ *result = gethostbyname(name); -#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_GETHOSTBYNAME_R) - - /* - * Use 'buffer' memory for storage of structures used by struct hostent. - * The layout is: - * - * addr pointers - * alias pointers - * addr structures - * alias structures - * name - */ - if (*result) - { - int i, pointers = 2 /* for nulls */, len = 0; - char **pbuffer; - - for (i = 0; (*result)->h_addr_list[i]; i++, pointers++) - len += (*result)->h_length; - for (i = 0; (*result)->h_aliases[i]; i++, pointers++) - len += (*result)->h_length; - - if (pointers * sizeof(char *) + MAXALIGN(len) + strlen((*result)->h_name) + 1 <= buflen) - { - memcpy(resultbuf, *result, sizeof(struct hostent)); - - pbuffer = (char **)buffer; - resultbuf->h_addr_list = pbuffer; - buffer += pointers * sizeof(char *); - - for (i = 0; (*result)->h_addr_list[i]; i++, pbuffer++) - { - memcpy(buffer, (*result)->h_addr_list[i], (*result)->h_length); - resultbuf->h_addr_list[i] = buffer; - buffer += (*result)->h_length; - } - resultbuf->h_addr_list[i] = NULL; - pbuffer++; - - resultbuf->h_aliases = pbuffer; - - for (i = 0; (*result)->h_aliases[i]; i++, pbuffer++) - { - memcpy(buffer, (*result)->h_aliases[i], (*result)->h_length); - resultbuf->h_aliases[i] = buffer; - buffer += (*result)->h_length; - } - resultbuf->h_aliases[i] = NULL; - pbuffer++; - - /* Place at end for cleaner alignment */ - buffer = MAXALIGN(buffer); - strcpy(buffer, (*result)->h_name); - resultbuf->h_name = buffer; - buffer += strlen(resultbuf->h_name) + 1; - - *result = resultbuf; - } - else - { - *result = NULL; - errno = ERANGE; - } - } -#endif - if (*result != NULL) *herrno = h_errno; -#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_GETHOSTBYNAME_R) - pthread_mutex_unlock(&gethostbyname_lock); -#endif - if (*result != NULL) return 0; else |